Optically active esters and optically active carboxylic acids are used in various fields such as pharmaceutical products, intermediates of biologically active substances, intermediates of natural product synthesis, and the like.
In the background art, as a method for producing an optically active ester, a method of production from a racemic secondary benzyl alcohol in the presence of an acid anhydride, using tetramisole or benzotetramisole as a catalyst has been known (see Non-Patent Document 1). Further, a method for producing an optically active ester from a racemic propargylic alcohol in the presence of an acid anhydride using benzotetramisole as a catalyst has been known (see Non-Patent Document 2). However, these production methods have the problem that the structures of the acid anhydride are very limited, and the like, and the substrate generality is poor. Thus, the present inventors have previously proposed a method for producing an optically active ester by reacting a racemic secondary benzyl alcohol and a free carboxylic acid in the presence of a benzoic anhydride or its derivative, using tetramisole or benzotetramisole as a catalyst (see Non-Patent Document 3).
On the other hand, as a method for producing an optically active carboxylic acid, a method of crystallization separation of a diastereomer salt of a racemic carboxylic acid and a separation agent, using an optically active amine as a separation agent has been known (see Patent Document 1). However, this production method has the problems of high substrate specificity, and that the identification of an optically active amine suitable for the structure of the carboxylic acid, and the selection of the recrystallization solvent are difficult. Further, because the separation is repeated multiple times, the operation is complicated.    Non-Patent Document 1: Birman, V. B.; Li, X.; Org. Lett.; 2006, 7, pp. 1351-1354    Non-Patent Document 2: Birman, V. B.; Guo, L.; Org. Lett.; 2006, 21, pp. 4859-4861    Non-Patent Document 3: Shiina, I.; Nakata, K.; Tetrahedron Lett.; 2007, 48, pp. 8314-8317    Patent Document 1: Japanese Unexamined Patent Publication No. H9-143101